1. Field of the Invention
The present invention relates to movie cameras, and more particularly, to a movie camera with a strobe light for shooting a still shot or picture in synchrony with a flash of the strobe light.
2. Description of the Related Art
Recently, a type of video camera whereby moving pictures (hereafter referred to as a "movie") can be easily produced, is becoming popular. In a movie camera of this type, image information is recorded by a magnetic head on a magnetic tape housed in a video cassette. Movie images of, for instance, scenes from various sports shot by the movie camera are reproduced on a cathode-ray tube (CRT) and watched by, for instance, people who want to analyze their form during their play.
Such cameras employ a solid state sensing device for converting image information corresponding to light incident thereon, into electrical signals. A common device is a charge coupled device (CCD). Furthermore, a CCD may have an electronic "shutter", briefly explained as follows, with details specified in Japanese Application No. 63-282600, Laid-Open No. 1990-130080 (Kamikubota et al). The storage time for such a device has a first period, wherein all charges stored are discarded at the end thereof, followed immediately by a second period, wherein all charges stored are read and outputted. In this way, the CCD has an electronic "shutter", wherein the "shutter" is "closed" during the first period and "opened" during the second period.
For these usages of the movie camera, it is advantageous to develop a method for obtaining clear successive pictures free of a blur of the subject, shot at a high shutter speed using a strobe light. However, if the strobe light is flashed without synchronization with the storing time of the CCD, uniform brightness between pictures cannot be expected because the amount of exposing light differs from picture to picture. On the other hand, pictures of a subject moving at a high speed and shot at a low shutter speed have much blur.
Further, there is a problem of sudden fall of gain in an automatic gain control (AGC) circuit when a strobe light is used, because of the sudden increase of amount of light. The AGC circuit requires a relatively long time until the fall of gain is recovered, and hence there arises a problem that the brightness fluctuates between pictures shot after and before a flash of the strobe light.